1. Field of the Invention
The present invention relates generally to an electronic messaging system that is capable of processing encoded messages and information. In particular, the disclosure is directed to a system in which an electronic message server performs at least a portion of the verification functions typically performed by a mobile wireless communications device having secure electronic messaging capability, wherein the electronic message server, in addition to providing an indication of whether a message has been verified by the server, provides information to the mobile wireless communications device so that the device can perform additional trust, validity and strength checks, or the like.
2. Related Art
Exchanging cryptographically encoded secure electronic messages and data, such as, for example, e-mail messages, is well known. In many known electronic message exchange schemes, signatures, encryption or both are commonly used to ensure the integrity and confidentiality of information being exchanged between a sender and a recipient of the electronic messages. In an e-mail system, for example, the sender of an e-mail message may either sign the message, encrypt the message or both sign and encrypt the message. These actions may be performed using well-known standards, such as, for example, Secure Multipurpose Internet Mail Extensions (S/MIME), Pretty Good Privacy™ (PGP™), OpenPGP, and numerous other secure e-mail standards.
In general, secure e-mail messages are relatively large. For example, S/MIME can increase the size of an e-mail message by a factor of ten or more in some situations. This size augmentation presents difficulties, especially in devices that have a limit on the size of a message that can be processed, such as, for example, a mobile wireless communications device. Such a device may also experience difficulty handling a message wherein only a portion of the message has been transferred to the device because of the above-mentioned size limitations.
For example, if a message is larger than the size limit of the device, then the entire message will never reach the device. If this large message is a signed or encoded message, then all the data required to verify the signature may not be sent to the device, and thus, the device may not be able to verify the signature.
Exemplary solutions wherein an electronic message server performs some or all of the verification functions typically performed by the device are described in co-pending, commonly assigned U.S. patent application Ser. No. 10/914,634 entitled “Server Verification of Secure Electronic Messages” and U.S. patent application Ser. No. 10/916,098 (now U.S. Pat. No. 8,335,823), entitled “System and Method for Processing Encoded Messages,” the disclosures of which are incorporated by reference herein in their entirety. In these applications, various systems and methods for providing server-based verification of electronic messages are described. Typically, these solutions provide an indication to a device that a message or digital signature appended to the message has been verified by the server. Additionally, these solutions may provide partial processing of a large electronic message to assist the device in completing its own verification process. As a further enhancement to these solutions, it is envisioned that additional information may be provided to the device so that the device can perform additional trust, validity and strength checks, or the like, on the message, if the user desires.